HELP first fish fin rot?

[kjardine519]

Hello I am still new in this Hobbie, it appears to me my fish has fin rot.
Tank specs are
35 gal dt
30 gal sump
Bubble mag 3.5 skim
35 lbs of rock

Tank prams
Salinity 1.0205
Nitrite 0
Ammonia 0
Nitrate 40 ppm :0

I have peroxide at home, should I dose some? Any clue on how much? I also have 3 hermit crabs and a turbo snail. And 2 small colony's of zoas.
Tank is six weeks old

 

[kjardine519]

He's also got some darkness around his gills?

 

[HumbleFish]

You can't dose anything in a DT that will help with that without putting your snails, crabs, zoas at risk. However, you can soak his food in vitamin supplements (vita-chem, selcon, zoecon) to give his immune system a boost.

 

[kjardine519]

Ah okay, thanks